Vitamin E and its derivatives are substances which by virtue of their presumed properties as antioxidants and removers of free radicals, are widely used in the pharmaceutics and cosmetics industry in the preparation of formulations for treating skin diseases, or for combating or preventing unsightly skin conditions.
For these reasons, vitamin E and its derivatives are often present in cosmetic formulations as "active" components in variable concentrations ranging between 1% and 25%, although the antioxidant and anti-ageing action of vitamin E at a skin level has never been scientifically proved.
On the contrary, it has recently been experimentally proved (see patent application WO 98/10793 by the same Applicant) that vitamin E acetate has physical-chemical properties such as to make it suitable for use as main component of the lipophilic phase of ointments.
In fact, vitamin E acetate is particularly easy to spread, is absorbed surprisingly quickly, produces no unpleasant thermal sensations, leaves the skin shiny only for a few minutes, and then leaves it soft, elastic and not sticky; in addition, it resists to cleansing with water or detergents.
In addition, since vitamin E acetate is not a molecule foreign to the human organism, it can easily integrate with the lipids present in the cornified layer, thus facilitating absorption through the skin of substances dispersed into it.
Among the other formulations for topical use, the above patent application disclosed and claimed a hydrophobic gel preparation comprising a cyclomethicone and dimethiconol mixture, preferably having a 8:2 weight ratio.
Two examples of said formulation had been provided, too, in which vitamin E acetate made up 20% and 30% respectively of the total weight of the composition, the rest of which comprised a 8:2 cyclomethicone/dimethiconol mixture and, optionally, 5% of hydrogenated castor oil.
These hydrophobic gels actually proved excellent formulations for cosmetic use when used as they are, and very good carriers of pharmaceutically active substances.
Nevertheless, it has been observed that hydrophobic gels thus formulated in the end showed a certain tendency to separate a liquid phase, i.e. a certain tendency to syneresis.